Just Bob

Nope. You shouldn't do that either. This is a mystery that has not yet been solved.

For the sake of accuracy: the 1968 Kennedy, while 40% silver as you said, is made up of two outer layers of 80% silver and 20% copper, bonded to a core of 21.5% silver and 78.5% copper. That makes it 40/60 silver/copper. So, what you are actually seeing under the tissue is 80% silver.

I'm not. I think they are copper-nickel, and the additional thickness - judging by your picture - accounts for the additional weight. Add the tissue test results to that, and I don't think they are silver. I have been wrong more than once, though.

It is neither. It is a novelty piece.

I have this mental picture of these guys standing around the parking lot, wearing t-shirts and black leather jackets, slicked back 50's hairdo, (feather-do?) matchstick hanging from the Bald Eagles beak, whistling at the Sparrows as they walk by.

Well, I guess a little is better than none at all. Would you mind providing a link to a page where NGC calls machine doubling an error? I can't seem to find it on my own.

MS62 and MS63, respectively. That is on my phone. Looking at them on the laptop may be a different story.

I hate it when that happens.

This is a quote from an earlier thread, posted by Conder101: "Tissue test. Put a single layer of tissue paper over them. Clad proofs will appear gray, silver proofs will appear white. This works whether they are in their original cases or not. A quick easy test and good if it isn't possible to see the edge or weigh them." 

Even my wife, who knows nothing about coins, looked at the picture and said, "That's a little too much."

Sometimes they don't. I am still trying to find out why I can't see who likes my (or any other) posts. Any way, back to your coins. I can see the haze on the first few coins, especially the quarter, and I can see why you would want to change the look of at least that particular one, but, if the multiholder were mine, I think I would leave it as is. They don't make those for regular customers any more - just for bulk submitters, I think - and the novelty of it really appeals to me. Just my opinion, though. Your mileage may vary. Welcome to the forum.

Ditto.No pictures on my phone or my laptop.

The altered letters are a result of damage. They did not happen at the mint.

Does the tissue test work with proofs?

The close AM was normal for that year, so no premium for that. Sorry.